# directory-same-package

Source: https://apigenie.pl/docs/linter/protobuf/rules/directory-same-package

This rule checks whether all the `.proto` files of a directory declare the same package.

## Rule Details

Many code generators, for example the Go one, turn a directory into a single package of the
generated code. Files of different Protobuf packages in one directory then produce code that does
not compile, and they make the layout of the API harder to follow.

The `directory-same-package` rule compares the package of the linted file with the packages of
the other `.proto` files in the same directory (subdirectories are not included). If any of them
declares another package, or no package while the linted file has one (or the other way round),
the rule reports:

`Other files of the directory declare other packages: <files>`

where `<files>` lists each such file as `'<package>' (<file name>)`, or as
`no package (<file name>)` when the file has no package. The issue is reported at the package
declaration, or at the syntax statement of a file without a package.

Files of the directory that cannot be read, for example because of syntax errors, or because they
are proto2 or editions files, are ignored.

## Configuration

This rule has no options.

## Examples

**Good**. The directory `acme/pets/v1` contains `pet.proto`:

```proto
syntax = "proto3";

package acme.pets.v1;

message Pet {
  string name = 1;
}
```

and `owner.proto`:

```proto
syntax = "proto3";

package acme.pets.v1;

message Owner {
  string name = 1;
}
```

**Bad**. The directory `acme/pets/v1` contains the same `pet.proto` as above, and this
`owner.proto`:

```proto
syntax = "proto3";

package acme.owners.v1;

message Owner {
  string name = 1;
}
```

The linter reports
`Other files of the directory declare other packages: 'acme.owners.v1' (owner.proto)` in
`pet.proto`, and
`Other files of the directory declare other packages: 'acme.pets.v1' (pet.proto)` in
`owner.proto`.

## When Not to Use It

You may disable this rule if your build tools and code generators do not map directories to
packages, and you deliberately keep several packages in one directory.

## Compatibility

This rule is compatible with proto3 files. proto2 and editions files are rejected by the reader
and are not linted. The rule reads the other `.proto` files in the directory of the linted file.